As will be appreciated herein below, except as otherwise indicated, aluminium alloy designations and temper designations refer to the Aluminum Association designations in Aluminum Standards and Data and the Registration Records, as published by the Aluminum Association in 2009.
For any description of alloy compositions or preferred alloy compositions, all references to percentages are by weight percent unless otherwise indicated.
In the production of motor vehicles in particular aluminium alloys the AA5xxx- and AA6xxx-series alloys like 5051, 5182, 5454, 5754, 6009, 6016, 6022, and 6111, have been used to produce body panels and structural parts or body-in-white (“BIW”) parts.
There is a demand for the use of aluminium alloys, in particular for formed BIW parts, which are formable and having increased strength after being subjected to a paint bake cycle. Typical targets for the mechanical properties are a yield strength or Rp0.2 of over 500 MPa after the paint bake cycle.
In addition, the properties normally required for BIW parts include:
a high formability for the forming operation, typically by means of stamping, deep drawing, or roll forming,
high mechanical strength after paint baking so as to enabling down gauging thus minimising the weight of the part,
good behaviour in the various assembly methods used in motor vehicle manufacturing such as spot welding, laser welding, laser brazing, clinching or riveting, and
an acceptable cost for mass production.